Distribution and historical aspects of Brazilian Stachytarpheta (Verbenaceae): Exploring a comprehensive dataset of taxonomically verified specimens

Abstract

Stachytarpheta (Verbenaceae) encompasses approximately 120 species distributed throughout tropical and subtropical regions of the Americas, with Brazil boasting the highest species richness (90 spp.) and endemism (82 spp.). This study introduces an updated, taxonomically revised, and credible occurrence dataset focusing on Stachytarpheta species in Brazil, comprising 4,843 records. This dataset results from expert revision of herbarium collections and integration with global repositories, notably GBIF, alongside national repositories like REFLORA and speciesLink. It facilitates a thorough exploration of the temporal, geographical, and taxonomic patterns of Stachytarpheta across diverse regions and landscapes in Brazil. Stachytarpheta species and their occurrence records are concentrated in the states of Minas Gerais, Bahia, and Goiás, particularly in the campo rupestre and savanna formations of the Espinhaço Range and Chapada dos Veadeiros. Analysis of potential biases within our dataset revealed a strong correlation between specimen occurrences and proximity to roads. Rarefaction curves indicate ongoing potential for species discovery within the Cerrado and Caatinga domains, with the Tocantins state emerging as a particularly promising area for novel findings; therefore, presenting opportunities for exploration. The majority of the specimens are housed in Brazilian herbaria, particularly at RB, HUEFS, and CESJ. Temporal analysis of occurrence records showed an upward trend during the 20th century and the first decade of the 21st century, which can be largely attributed to the efforts of generalist collectors working mostly in Eastern and Central Brazil. Most collection efforts were carried out through Brazilian and European initiatives, often supported by local funding, especially during the mid-20th century. However, funding for scientific initiatives in Brazil has waned since the mid-2010s, potentially affecting recent trends in species recording. Our dataset serves as a resource enabling subsequent analysis delving into the systematics, biogeography, and conservation of this remarkable genus from open vegetation formations in Brazil.